Disentangling the dynamical origin of P11 Nucleon Resonances

Abstract

We show that two almost degenerate poles near the $\pi \Delta$ threshold and the next higher mass pole in the $P_{11}$ partial wave of $\pi N$ scattering evolve from a single bare state through its coupling with $\pi N$, $\eta N$ and $\pi \pi N$ reaction channels. This finding provides new information on understanding the dynamical origins of the Roper $N^{\ast }(1440)$ and $N^{\ast }(1710)$ resonances listed by Particle Data Group. Our results for the resonance poles in other $\pi N$ partial waves are also presented.

Comments: Improved version, accepted Phys. Rev. Lett